Radio 1 presenter Sian Eleri investigates a seemingly ordinary farmhouse in north Wales, which, in the late 1990s, was widely considered the most haunted house in Britain. The story made local and national headlines as the family who lived at the farm became ever more desperate in their search for answers. More than 300 allegedly paranormal events were documented at the Flintshire farmhouse in video footage, audio interviews, photos and eyewitness accounts – all of which has been locked away until now.

Sian is frustrated that she still hasn’t been able to contact the Gower family who lived at the farmhouse – David, a former headmaster, his wife Rose-Mary and their son John-Paul. But there is a breakthrough of another kind when the current owner of Penyffordd Farm gets in touch and invites her over to see the house she’s heard so much about.

Sian Eleri’s investigation into the haunting of Penyffordd Farm continues as multiple witnesses claim to have seen a hooded figure. Could they all have imagined the same thing?

Sian's investigation into an allegedly haunted house in north Wales concludes. Can she track down the last family members and solve whether this was paranormal or all a hoax?

Sian Eleri delves into reports of the biggest mass UFO sighting in Britain. Her first mission is to track down the schoolboys whose 'alien' encounter in west Wales triggered it all.

Reeling from Rosa’s account of being woken by a bright light and seeing creatures', Sian heads to Rosa’s hilltop hotel, where she claimed they 'landed' to find her.

Sian’s mind is blown to discover reports of hundreds of UFO sightings across south Wales. Could they all have imagined seeing the same object in the sky?

Sian dives deeper than ever as her investigation concludes. Will eyewitness accounts and recently unclassified documents deliver a rational explanation or something more sinister?

Radio 1 Presenter Sian Eleri investigates the story of Scottish medium Helen Duncan, who in 1944 became the last person convicted and imprisoned under the Witchcraft Act. As the Blitz rained down on London, Helen went on trail at the Old Bailey in a case that would make headlines around the world. Revered by her supporters, who believed she had the power to bring back spirits of the dead, Helen became the most notorious medium in history, and people flocked to have seances with her. Sian begins by tracking down former criminal lawyer Graham Hewitt, who is fighting to pardon Helen on behalf of her surviving family members. Sian discovers it was actually fraud for which Helen was put in prison using witchcraft law, but Graham highlights what he believes is inexplicable evidence from her trial that proves otherwise.

There is an unnerving breakthrough in Sian’s investigation into a woman who claimed to summon spirits of the dead when she finds an audio recording of a Helen Duncan seance. Not only is a gravelly male 'spirit' heard to speak, but the people gathered comment that they see and recognise him. How is this possible? Sian tests out different theories – was it someone else speaking? Helen putting on voices? Did she have accomplices? How does that explain someone recognising a dead relative? Searching for answers and hoping to understand how Helen was convincing people they were communicating with their dead loved ones, Sian tracks down a modern-day medium. He claims to commune with the other side, but a seance in Edinburgh leaves Sian with more questions than she first started with. And Helen’s claims to be able to manifest the physical dead also take things to another level to what she has just experienced.

There’s only a handful of mediums worldwide who claim to do anything close to what Helen Duncan said she could and physically manifest spirits into a room. For Sian, the only way to fully understand what was happening at Helen’s séances is to witness this for herself, so she tracks one of these rare mediums down in the Netherlands. Sian arrives at the Dutch monastery and is greeted by a host who takes Sian on a private tour of the séance room, where the medium will work that evening. The traditions haven’t changed much since Helen’s 1930s séances. The medium will be searched, then tied to a chair, enclosed behind a black curtain, and spirits, depending on what unfolds that night, may physically 'appear'. The room will be pitch black, and Sian will be locked inside.

Sian’s mission to get to the truth behind Helen Duncan’s apparently supernatural abilities draws to a close – but a secret package sent from Helen’s granddaughter in America leaves Sian with what appears to be the smoking gun she has been waiting for. The package contains what seems to be unexplainable proof that a 'spirit' revealed the sinking of a second warship during one of Helen’s séances. But this time, the séance happened before even the government was aware. Sian tussles with the few explanations still on the table – was this information received from beyond the grave? Or could Helen Duncan have been a spy and in league with the enemy? Wherever the truth lies, Sian feels increasingly sure there was more to Helen’s Old Bailey trial and conviction than a case of fraud.